JPH0216778A - Optical coupling type semiconductor relay device - Google Patents

Abstract

PURPOSE:To miniaturize the device by laminating a photoelectric converter element on a longitudinal MOSFET through an insulating film, and forming the longitudinal MOSFET on a single semiconductor substrate so as to also use the substrate as a drain. CONSTITUTION:A light emitting section 4 and an optical detector section are disposed in opposition in the vicinities of the tip ends of lead frames 2, 3. Resin 6 is disposed between the light emitting section 4 and the optical detector section 5, the resin being capable of transmission of light emitted from the light emitting section 4. A longitudinal MOSFETs 8, 9 where photodiode arrays are laminated through insulating films are formed on the same semiconductor substrate 10. These FETs are connected to each other by using in common the substrate 10 as a drain.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a semiconductor relay device, and in particular to an AC relay device that includes a light emitting section that emits an optical signal and a light receiving section that performs a switching operation based on the optical signal. The present invention relates to a DC-common optically coupled semiconductor relay device.

(Prior Art) Until now, electromagnetic relay devices have been mainly used as devices for controlling an output side circuit electrically isolated from the input side circuit based on a signal given to the input side circuit. . However, the electromagnetic relay device.

The device itself is large because it has mechanically moving parts.
It is difficult to miniaturize equipment using this device. Also,
In electromagnetic relay devices, the mechanical moving parts are prone to fatigue.
The drawback is that it has a short lifespan.

In recent years, in place of such electromagnetic relay devices, 5SR (SolidSt
A semiconductor relay device called ATE Relay is becoming popular. However, for example, semiconductor relay devices using bipolar transistors and thyristors.

AC and DC cannot be shared.

In order to solve these problems, a semiconductor relay device has been developed that uses two MOS field effect transistors (MOS Ft!T) and is capable of sharing AC and DC. This is an optically coupled semiconductor relay device consisting of a light emitting section consisting of one light emitting diode, and a light receiving section consisting of a photodiode and a MOS FET. FIG. 7 shows the equivalent circuit.

The photodiode arrays 41 and 42 in the light receiving section receive the optical signal emitted from the light emitting diode 38 in the light emitting section and perform photoelectric conversion, and the resulting electromotive force is used to send the MOS FET 39.
, 40. The source electrodes of the MOS PETs 39.40 are connected to each other, and the electromotive force of the photodiode arrays 41 and 42 is the same as that of the MOS FETs 39.40.
40 is applied between the gate electrode and the source electrode. In this way, the current flowing between each drain of MOS FET 39,40 is controlled.

The above optically coupled semiconductor relay device includes one light emitting diode and two photodiode arrays.

A total of five elements, two MOS FETs, are required. As a method for downsizing a semiconductor relay device and reducing manufacturing costs by further reducing the number of elements used, a method has been proposed in which a photodiode array is stacked on a vertical MOS FET with an insulating film interposed therebetween. If this method is adopted, since the MOS FET and the photodiode are integrated, an optically coupled semiconductor relay device can be realized with a total of three elements.

(Problem to be Solved by the Invention) However, in the above method, it is necessary to provide wiring between two vertical MO3FETs in which photodiode arrays are stacked. Therefore, manufacturing costs still remain high, and there are limits to miniaturization.

The present invention solves the above-mentioned conventional problems, and its purpose is to further reduce the size and manufacturing cost of AC/DC current by configuring the light receiving section with one element. An object of the present invention is to provide a shared optically coupled semiconductor relay device.

(Means for Solving the Problems) The optically coupled semiconductor relay device of the present invention is an optically coupled semiconductor relay device comprising a light emitting section having two light emitting elements and a light receiving section optically coupled to the light emitting section. Therefore, the light receiving part is
a plurality of vertical field effect transistors formed on one semiconductor substrate so as to share the substrate as a drain;
A photoelectric conversion element is formed above each of the vertical field effect transistors with an insulating film interposed therebetween, thereby achieving the above object.

For example, a light emitting diode is used as the light emitting element constituting the light emitting section. light emitting diode.

It is a diode that emits visible or near-visible light when a voltage is applied. On the other hand, a photodiode, for example, is used as the photoelectric exchange element 9 constituting the light receiving section. A photodiode is a diode that generates photocurrent or photovoltaic force when irradiated with light of a predetermined wavelength. The light emitting diode and photodiode described above are selected to have a wavelength band such that they can be optically coupled.

An equivalent circuit of the optically coupled semiconductor relay device of the present invention is expressed as shown in FIG. 6, for example. The light emitting diode 33 constituting the light emitting section converts the applied input electrical signal into an optical signal. Optical signals emitted from the light emitting diode 33 reach photodiode arrays 34 and 35 that constitute the light receiving section. In Figure 6, a set of photodiode arrays 34.3
Although one light emitting diode 33 is used for every photodiode array 34, 35, one light emitting diode may be used opposite each of the photodiode arrays 34,35.

Photodiode arrays 34, 35 convert the received optical signals into electrical signals. The electrical signal is given in the form of an electromotive force and drives vertical MOS FETs 36 and 37.

The drain electrodes of the vertical MOS PETs 36, 37 are connected to each other, and the electromotive force of the photodiode array 34, 35 is applied between the gate electrode and source electrode of the vertical MO5FET 36, 37, respectively. In this way.

The current flowing between each source of the vertical MO5FET 36, 37 is controlled.

In the optically coupled semiconductor relay device of the present invention, the photoelectric conversion element is stacked on a vertical MOS FET with an insulating film interposed therebetween. Moreover, the vertical MO3FET is formed on one semiconductor substrate so as to share the substrate as a drain. Therefore, by integrating these elements constituting the light receiving section, miniaturization becomes possible. Furthermore, manufacturing costs are also reduced by reducing the number of elements.

(Example) Examples of the present invention will be described below.

FIG. 2 is a sectional view showing the structure of an optically coupled semiconductor relay device 1 which is an embodiment of the present invention. Lead frame 2, 3
There is a light emitting part 4 and a light receiving part 5 near each tip of the
are arranged so as to face each other. A light emitting diode is used as a light emitting element constituting the light emitting section 4.

A resin 6 is disposed between the light emitting section 4 and the light receiving section 5 and is capable of transmitting the optical signal emitted from the light emitting section 4 . The entire area near the tips of the lead frames 2 and 3 is coated with a light-shielding resin 7 to prevent malfunctions caused by external light.

FIG. 3 is a schematic diagram of the surface of the light receiving section 5 viewed from above. A photodiode array was used as the photoelectric conversion element. Vertical type M in which photodiode arrays are stacked via an insulating film
O3l? ET 8. 9 are formed on the same semiconductor substrate 10. These vertical MO5FETs 8.9 are connected to each other by sharing the semiconductor substrate ttFi10 as a drain. A guard ring 11 is installed around each vertical MO5FET 8.9 to increase pressure resistance.
．． 12 are formed.

FIG. 1 is a partial perspective view of the vertical MOS FET 8 or 9 of FIG. 3 with a stacked photodiode array.

Vertical MO5FET like this 8. 9 will be explained. A 30 μm N-3i pittaxial layer 14 is grown on the N''-5i substrate 13, and boron ions are partially implanted using a resist mask to form island-shaped P.
Region 15 was formed. Next, an N'' region 16 was formed in the center of the island-shaped P region 15 by annularly implanting phosphorus ions using a resist mask. A gate insulating film 17 was formed by thermally oxidizing the entire surface. Thereafter, an N''-3i polycrystalline film 18, which would become a gate electrode, was formed over the entire surface.

Next, etching was performed using normal lamination lithography.
As shown in FIG. 1, the gate insulating film 17 and the N"-Si polycrystalline film 18 were left only outside the annular N" region 16. After forming a SiO□ film 19 over the entire surface, a boron-doped Si non-single crystal film was formed and irradiated with an argon laser to obtain a P-Si single crystal film. Instead of the argon laser, another laser that emits laser light with a wavelength that is absorbed by the Si non-single crystal film may be used. Alternatively, instead of irradiating with a laser beam, the Si non-single crystal film can be converted into a P-3i single crystal film by irradiating it with an electron beam or heating it using a lamp, heater, or the like.

This P--Si single crystal film was etched, leaving only the region where the photodiode would be formed. Remaining island-like P-Si
N″ region 21 was formed by ion-implanting arsenic into single crystal region 20 using a resist mask. In the part other than N° region 21 of island-shaped P-Si single crystal region 20,
P1 region 22 was formed by implanting boron ions using a resist mask. and.

After forming 23 SiO□ films on the entire surface, vertical MOS
The 5i02 film 19.23 on the source contact region and gate contact region (not shown) of the FET and the 5i02 film 23 on the N' contact region and P' contact region of the photodiode are opened by etching, and the Si
exposed the face.

Next, after forming an AI film on the entire surface, it was etched into a predetermined pattern to form At wirings 24 and 25.

Although not shown in FIG. 1, the At wirings 24 serving as source electrodes are connected to each other, and the At wirings 25 formed on the photodiodes at one end of the photodiode array are connected to each other.
and further connected. Also, N” which becomes the gate electrode
The -Si polycrystalline film 18 is connected to the photodiode at the other end of the photodiode array through the gate contact region.

Therefore, the equivalent circuit of the optically coupled semiconductor relay device of the two embodiments is shown in FIG. Finally, a 5iJ4 film (not shown) was formed as a surface protection film, and then etched to expose only the pad portions that will be in contact with external wiring.

FIG. 4 is a sectional view of the vicinity of the guard ring. The guard ring 26 is a P region, and was formed at the same time as the above-mentioned p 5i region 15 was formed. Also, on the guard ring 47)
S i 02 film 19.23 is as described above (7) S i Oz
When forming the films 19 and 23, the At electrode 27 on the SiO□ film 19 film shape 93 was formed at the same time as the above-mentioned At electrode 24 was formed.

In this embodiment, a photodiode was formed by ion-implanting arsenic into a P-Si single crystal film.

Conversely, a photodiode may be formed by ion-implanting boron into an N-5i single crystal film.

Vertical MO3 stacked photodiode array used in an optically coupled semiconductor relay device which is another embodiment of the present invention
A partial perspective view of the FET is shown in FIG.

The process up to the step of forming the 5ift film 19 over the entire surface is the same as the above embodiment.

Next, a nickel-chromium layer was formed on the entire surface of the Sing film 19, and then buttered to leave only the area where one photodiode was to be formed, forming an island-shaped lower electrode 28. After forming a P-5i amorphous film 29 on the entire surface and patterning so that a part of the island-shaped lower electrode 28 is exposed, an N-3i amorphous film 30 is further formed on the entire surface to form an island. The P-5i amorphous film 29 was patterned so as to cover the top and side surfaces of the P-5i amorphous film 29 and to expose a portion of the lower electrode 28.

Next, as an upper layer transparent electrode, an indium oxide film 31 containing tin is formed on the entire surface, and an island-shaped N-5i amorphous film 30 is formed.
It was patterned to cover the top and side surfaces of the photodiode and to connect the lower electrode 28 and the N-3i amorphous film 30 of the adjacent photodiode.

Finally, the 5in2 film 19 on the source contact region and gate contact region (not shown) of the vertical MO3PET.
An opening was opened by etching to expose the Si surface. After forming an A1 film on the entire surface, it was etched into a predetermined pattern to form an AI wiring 32. Although not shown in FIG. 5, the Δ] wirings 32 that serve as source electrodes are connected to each other and are further connected to an indium oxide film 31 containing tin formed on the photodiode at one end of the photodiode array. . Further, the N'-3i polycrystalline film 18 serving as the gate electrode is connected to the photodiode at the other end of the photodiode array through the gate contact region. Therefore, the equivalent circuit of the optically coupled semiconductor relay device of the two embodiments is also expressed as shown in FIG.

The structure near the guard ring is the same as that of the above embodiment except that the SiO□ film 23 is not present.

In this example, the N-3i amorphous film was formed on the P-3i amorphous film, but conversely, the P-5i amorphous film may be formed on the N-3i amorphous film. . Alternatively, a P-i-N structure or an N-1-P structure can also be adopted.

(Effects of the Invention) According to the present invention, as described above, a plurality of vertical MO5FE
By forming T on the same semiconductor substrate and using the substrate as a common drain, and by stacking photodiodes on each vertical MO3FET with an insulating film interposed therebetween, the light receiving section is formed by one element. A DC-common optically coupled semiconductor relay device is obtained. Such a semiconductor relay device is
It is more compact than conventional semiconductor relay devices,
In addition, manufacturing costs are reduced. Therefore, the optically coupled semiconductor relay device of the present invention can be widely applied in fields where conventional electromagnetic relay devices have been used.

4. Quantity 1 Figure 1 shows a vertical type M in which photodiode arrays are stacked in an optically coupled semiconductor relay device which is an embodiment of the present invention.
FIG. 2 is a sectional view of the optically coupled semiconductor relay device, and FIG. 3 is a perspective view showing the main parts of OS FBT 8 or 9.
4 is a cross-sectional view showing the vicinity of the guard ring 1112 shown in FIG. 3, and FIG. 5 is an optically coupled semiconductor relay according to another embodiment of the present invention. FIG. 6 is an equivalent circuit diagram of an optically coupled semiconductor relay device that is an embodiment of the present invention, and FIG. 7 is a conventional optically coupled semiconductor relay. FIG. 3 is an equivalent circuit diagram of the device.

1... Optically coupled semiconductor relay device for both AC and DC,
4... Light emitting part, 5... Light receiving part 28.9... Vertical MO5FET with stacked photodiode array, 10
...Semiconductor substrate, 13...N゛~Si~Si substrate・
・P region, 16.21...N' region 17...gate insulating film, 18...N''-5i polycrystalline film.

19, 23...5t04 film, 20...P-5i single crystal region, 22...P'' region 29...P-3i amorphous film 830...N-5i amorphous film, 34°35, 41.
42... Photodiode array, 36.37...
Vertical MO3FET, 39.40...Jios PE
T.

that's all

Claims (1)

[Claims] 1. An optically coupled semiconductor relay device comprising a light emitting section having a light emitting element and a light receiving section optically coupled to the light emitting section, the light receiving section comprising one semiconductor. A plurality of vertical field effect transistors formed on a substrate so as to share the substrate as a drain, and a photoelectric conversion element formed above each of the vertical field effect transistors with an insulating film interposed therebetween. Optically coupled semiconductor relay device.